Break-contact block with relatively movable bridge-like contacts

ABSTRACT

A break-contact block includes two identical half-housings that have compartments formed by partitions to accommodate bridge-like contacts and respective springs. Two foot sections with projections in different arrangements make it possible to maintain a smaller spacing or a larger spacing depending on the relative positions of the two half-housings that are joined together. This makes it possible to manufacture break-contact blocks for thick or thin busbars using identical parts.

FIELD OF THE INVENTION

This invention concerns a break-contact block for connecting anddisconnecting busbars that can move relative to each other. Thebreak-contact block comprises a housing and bridge-like contactsarranged parallel to each other in such a way that they can moverelative to each other in the housing. The bridge-like contacts havecontact faces at their ends for making contact with the busbars that areto be connected and they are biased against the busbars. Two contactsare arranged opposite each other to form parallel conducting paths. Suchbreak-contact blocks are used, for example, in electric switching unitsarranged in a manner that allows the circuit-breakers to be withdrawn.

BACKGROUND OF THE INVENTION

A break-contact block of this type is disclosed in European patent B107,611. The housing for this break-contact block is made of sheet metalparts that are riveted or bonded together. The spacing between thecontacts is maintained by spacers with arms that reach between thecontacts. Therefore, break-contact blocks with different housings areneeded, depending on the thickness of the busbars to be connected.However, the contacts and spacers can be used without any changes.

OBJECTS AND SUMMARY OF THE INVENTION

The object of this invention is to reduce the variety of models requiredfor these break-contact blocks.

According to this invention, this object is achieved by a housingcomprising two half-housings having certain foot sections that areprovided with passages for mounting elements that are intended formutual contact. The half-housings are also provided with partitions tosubdivide the space provided to accommodate the contacts. Thissubdivision of the housing of the break-contact block into half-housingsmakes it possible to manufacture break-contact blocks for busbars ofdifferent thicknesses by mounting the half-housings with the requireddistance between them. The partitions also make it possible to use alarger or smaller number of contacts or contacts with a greater orsmaller thickness as needed.

Within the scope of this invention, an especially advantageouspossibility of assembling the half-housings with two different fixedspacings consists of the fact that the foot sections have a base and atleast one projection with a face extending outward from the base. Theprojections are offset with respect to each other so that when twohalf-housings are joined in one position, at least one projection on onefoot section comes to rest with its face on the base of the oppositefoot section, thereby defining a relatively small distance between thetwo half-housings. However, when the two half-housings are joined in a180°-rotated position, the faces of the projections on opposing footsections come in contact, which thus defines a relatively great distancebetween the two half-housings.

With a refinement of the above-mentioned design of the foot sections, itis possible to ensure that if the mounting elements are used, the twohalf-housings will be aligned relative to each other without anymisalignment, despite the relatively small total area of the footsections. This can be accomplished by arranging the projections andrecesses in each foot section so they are symmetrical with the passagefor the respective mounting device. More specifically, a design isproposed where each of the two foot sections has four projections withessentially the same total cross section that can be joined to form aclosed shape to create the relatively small distance between thehalf-housings on the basis of their offset arrangement. This results ina stable but space-saving arrangement of the two half-housings,providing only a small distance between the two busbars that are to beconnected and thus relatively short contacts.

Each half-housing of the break-contact block may have two ribbedpedestal-shaped foot sections. In this regard it is advantageous for theribs to be designed so they form supporting faces for contact with anabutment. The significance of such a design will be discussed below.

With the prior art break-contact block described previously, the springsprovided for the contacts are supported on one rib of one of the partsof which the housing for the break-contact block is made. The springsare designed as spring-loaded arms of a simple part. According to oneimproved embodiment of this invention, however, it has proven to beadvantageous that a spring, designed as a bent wire spring whose curvedleg ends are in contact with a web that is runs across the partitions oneach half-housing, is provided for each contact. This has the advantagethat only one spring design is needed if the break-contact blocks are tobe produced with different numbers of contacts.

The above-mentioned web may have a rib that separates the ends of thelegs in order to center the wire spring. This centers the springs in thecompartments of the half-housings formed by the partitions, thusassuring a uniform contact force of the neighboring contacts.

To permit a certain equalization in the alignment of the busbars to beconnected, it is advisable for the contacts to have a rear surface withan outward curvature for supporting them on the springs approximately inthe middle.

The desired engaged length of the busbars in a break-contact block canbe achieved by providing aligned recesses in the partitions of thehalf-housings to accommodate a spacer that has a rounded projection forcoming in contact with the face of one of the busbars. The spacer keepsthe contacts at a suitable distance for insertion of the busbars. Theprojection permits a certain pivoting of the break-contact block tocompensate for errors in alignment.

As mentioned above, a preferred application for break-contact blocks ofthe present type would be for switchgear with relatively movablecircuit-breakers. In this case, the break-contact blocks are optionallyarranged on the circuit-breaker, in other words, so they are movable, orthey may be stationary, i.e., mounted on the framework of theswitchgear, and therefore they are always in contact with busbars on oneside. The break-contact block is especially suitable for the applicationdescribed here due to the above-mentioned supporting faces that areformed by the ribs of the foot sections. For this purpose, the abutmentsthat work together with the supporting faces may be part of an insulatedhousing that accommodates the break-contact block. A busbar projectsinto the insulated housing and is mounted by means of mounting elementsthat seal off the housing. The break-contact block is guided when movedthrough the supporting faces in the insulated housing and can adjust toa difference in alignment between the busbars without any negativeeffects on the quality of contact achieved with the busbars.

This invention is explained in greater detail below on the basis of theembodiment illustrated in the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross-section view of a break-contact blocktaken along the longitudinal direction of the busbars that are to beconnected.

FIG. 2 is a cross-section view of the break-contact block according toFIG. 1 in a section taken across the busbars that are to be connected.

FIG. 3 is a top view of the break-contact block according to FIGS. 1 and2.

FIGS. 4 and 5 correspond to FIGS. 1 and 2, but the half-housings thatform the break-contact block are mounted with a greater distance betweenthem than that illustrated in FIGS. 1 and 2.

FIG. 6 is a top view of the foot parts of the housing part of abreak-contact block.

FIG. 7 is a cross-sectional side view of the foot part according to FIG.6 of the housing part of a break-contact block.

FIG. 8 is a cross-section view and FIG. 9 is a front view of thehalf-housings according to FIGS. 6 and 7.

FIG. 10 is a cross-section view showing one example of the use of abreak-contact block according to this invention.

DETAILED DESCRIPTION

The break-contact block 1 according to FIGS. 1 to 5 is used to connectbusbars 2 and 3 (indicated with dotted lines in FIG. 1). These busbarsare in contact with but are not fully engaged with break-contactblock 1. Busbars 2 and 3 are connected by means of bridge-like contacts4 that have a convex contact area 5 at each end and a rear face 6 withan outward curvature. Contacts 4 are in contact with walls 8 and 9 ofone half-housing 10 at faces 7. Two identical half-housings 10 arejoined by means of foot sections 11 and 12 on the face (FIG. 2) andmounting elements 13 and 13' that pass through them. Suitable mountingelements include any type of screws, bolts and rivets.

As indicated by FIGS. 3 and 5, each of the half-housings 10 is providedwith partitions 14, so the half-housings are subdivided into individualcompartments, each of which accommodates one contact 4. The center parts16 of springs 15, which are in the form of bent wire springs, are incontact with the curved rear face 6 of contacts 4, and leg ends 17 aresupported on a web 18 of half-housing 10 running across partitions 14. Arib 19 of the web 18 projects between the leg ends 17 and therebycenters springs 15 with respect to contacts 14. As shown in greaterdetail in FIGS. 3 and 5, each of the compartments of half-housings 10contains two contacts 4 and two springs 15.

Foot sections 11 and 12 project like a pedestal away from the housingbody and are provided with ribs 21 for reinforcement. The foot sections11 and 12 are positioned opposite each other on the face of eachhalf-housing 10 to connect two identical half-housings. A comparison ofFIGS. 1 and 2 as well as FIGS. 4 and 5 shows that a smaller distance S1(break-contact block 1, FIGS. 1 and 2) or a larger distance S2(break-contact block 1', FIGS. 4 and 5) is formed, depending on theposition in which the two half-housings 10 are assembled. This is basedon the design of foot sections 11 and 12, which is discussed in greaterdetail below on the basis of FIGS. 6 to 9.

As FIG. 6 shows, each of the foot sections 11 and 12 has a passage 22 toaccommodate the mounting elements 13 and 13' that serve as fasteners,which are illustrated in FIGS. 2, 3 and 4. Starting from a base 23, footsection 11 has four prismatic projections 24 that are symmetrical aroundpassage 22. The opposite foot section 12 also has four projections 25that start from a base 23 and are also symmetrical with passage 22.However, projections 24 are offset with respect to projections 25 to theextent that there is a projection 25 precisely at the location wherethere is a space between projections 24 on the other foot section. Thesize of the projections and their spacing are selected so that a footsection 12 can be placed on foot section 11, and then projections 24 and25 can be joined, forming an essentially closed configuration that isapproximately parallelepiped-shaped. This yields the smaller spacing S1shown in FIG. 2. However, if two half-housings 10 are assembled in sucha way that foot section 11 comes in contact with a foot section 11 onanother half-housing 10 and foot section 12 comes in contact with thecorresponding foot section 12 on the other half-housing 10, then faces27 on projections 24 will contact each other and faces 27 on projections25 will contact each other. This then yields the larger spacing S2 shownin FIG. 5. In this case, longer mounting elements 13' are providedinstead of mounting elements 13.

The difference between spacings S1 and S2 can be influenced by selectingthe length of projections 24 and 25 accordingly. It is also possible toachieve a third spacing distance that is between spacings S1 and S2 byproviding a filler piece that can be inserted into the spaces betweenprojections 26.

In the embodiment described here, the half-housings each have a footsection on opposite sides. Consequently, the half-housings are joinedtogether reliably and nevertheless the space between the half-housingsis restricted very little. However, the half-housings can be providedwith a larger number of foot sections if additional connections aredesired because of certain requirements regarding the dimensions, thestrength or similar features.

As shown especially in FIGS. 6 and 7, partitions 14 have alignedrecesses 30 into which a spacer 31 is inserted. The spacer 31 is shownin FIG. 1. Contacts 4 are held at a distance by spacer 31 such thatbusbars 2 and 3 can be inserted. Spacer 31 is provided with a roundedprojection 32 on its side facing busbar 3, which permits a pivotingmovement of the break-contact block 1 relative to busbar 8 when thelatter is accommodated between contacts 4.

The interaction of spacer 31 with other features of break-contact block1 or 1' is explained below on the basis of FIG. 10, which illustratesone application of a switchgear with a draw-out circuit-breaker. Thebreak-contact block mentioned above is accommodated in a recess 33 of aninsulated housing 34 that is provided for a stationary mount in theswitchgear. FIG. 10 shows a section through one of a total of sixconnection points that are needed when a triple-pole circuit-breaker isto be connected to stationary busbars. Stationary busbar 35 associatedwith break-contact block 1 is mounted on insulated housing 34 by meansof two mounting brackets 36. Contacts 4 of break-contact block 1 areengaged with the end of busbar 35, while the opposite busbar 37 of thecircuit-breaker (not shown) is illustrated as being some distance awayfrom an insertion orifice 40 of insulated housing 34. Busbar 37 can bemade to engage with contacts 4 by moving it in the direction of arrow41.

As FIG. 10 shows, break-contact block 1 is in contact with a face 42 ofbusbar 35 by means of rounded projections 32. Furthermore, convexabutments 43 of insulated housing 34 are each opposite a face 44 that isformed by ribs 21 of half-housings 10 (FIGS. 3, 5). This arrangementpermits an approximately parallel sliding movement of break-contactblock 1 in recess 33 to equalize the tolerance with an axial offset ofbusbars 35 and 37. Break-contact block 1 is thus supported so it floats,so to speak, in recess 33 of insulated housing 34. This assures a goodcurrent transfer between busbars 35 and 37 with little heating of thecontacts accordingly.

I claim:
 1. A break-contact block for connecting or isolating busbarsthat can be moved relative to each other, said break-contact blockcomprising:a housing; and bridge-like contacts arranged parallel to eachother in the housing, said contacts being movable relative to each otherand having contact faces at ends thereof for contacting the busbars tobe connected, said contacts being biased by springs against the busbars,and wherein two sets of said contacts are positioned opposite each otherto form parallel current paths, wherein the housing comprises twohalf-housings, each having foot sections for supporting the footsections of the other, said half-housings also including passages forreceiving mounting elements, and said half-housings including partitionsfor subdividing space accommodating the contacts.
 2. The break-contactblock of claim 1, wherein the foot sections each have a base and atleast one projection extending from the base, wherein the projections ofsaid foot sections are offset relative to each other such that when thetwo half-housings are joined in one position, the at least oneprojection of one foot section has a face in contact with the base of anopposite foot section, forming a relatively small distance between thetwo half-housings, and wherein when the two half-housings are joinedtogether in an offset arrangement where one of the two half-housings isrotated by 180 relative to another one of the two half-housings fromsaid one position, the projections on opposing foot sections are incontact at their faces, forming a larger distance between the twohalf-housings.
 3. The break-contact block of claim 2, wherein each footsection includes a plurality of projections symmetrically positionedwith respect to a passage for a mounting element.
 4. The break-contactblock of claim 3, wherein each of the foot sections has four projectionswith generally the same total cross section, said projections adapted tobe joined together in a closed configuration to form the relativelysmall spacing between the half-housings from the offset arrangement. 5.The break-contact block of claim 1, wherein each half-housing has twofoot sections each having a pedestal shape and including ribs.
 6. Thebreak-contact block of claim 5, wherein the ribs each include asupporting face to support an abutment of an insulated housing.
 7. Thebreak-contact block of claim 1, wherein said springs comprise bent wiresprings, each associated with a contact, and said springs each includecurved leg ends in contact with a web extending across the partitions oneach of the half-housings.
 8. The break-contact block of claim 7,wherein the web has a rib separating the leg ends of the springs forcentering the springs.
 9. The break-contact block of claim 1, whereineach contact has a rear face with an outward curvature for supportingsaid contact on one of the springs approximately at a center of saidcontact.
 10. The break-contact block of claim 1, wherein the partitionshave aligned recesses to accommodate a spacer having a roundedprojection for contacting a face of a busbar and keeping the contacts asuitable distance apart for insertion of the busbars.
 11. Thebreak-contact block of claim 6, wherein the break-contact block isadapted to be accommodated by an insulated housing having one or moreabutments, and a busbar is attached by means of holding elements thatseal off the insulated housing.